The launch of Mercedes-AMG's One hypercar has been pushed back to mid-to-late 2020. That's the word of AMG boss Tobias Moers who spoke recently with Top Gear magazine.

The One was previewed in prototype form as the Project One at the 2017 Frankfurt auto show and confirmed at the time for a launch in 2019. But getting the car's Formula 1 engine suitable for road duty—certainly no easy feat—is taking longer than expected.

“We have a delay; it’s not a secret,” Moers said. “There were some adjustments to be made on the powertrain.”

Tobias Moers

Tobias Moers

He went on to explain that there are many issues, singling out a stable idle as one that's particularly challenging.

The 1.6-liter turbocharged V-6 at the heart of the One's hybrid powertrain normally idles at 5,000 rpm in Mercedes-AMG's F1 race cars, but for road use AMG needs to get the idle down to 1,200 rpm while still meeting emissions regulations.

“You have leakage in the throttles in Formula 1 and nobody cares, because it runs at a 5,000-rpm idle,” Moers gave as an example of one of the issues. “At a 1,200-rpm idle, you have to meet the emissions regulations. You need a stable, proper idle. If it’s unstable, your emissions are unstable.”

Mercedes AMG W07 Hybrid 2016 Formula One car power unit

Mercedes AMG W07 Hybrid 2016 Formula One car power unit

Moers and his team at AMG are working closely with Mercedes-AMG High Performance Powertrains (HPP) in the United Kingdom to sort the issues. HPP is the division that develops and builds the Mercedes-AMG F1 team's engines and has been integral in the development of the One hypercar.

The good news is that the project is now back on track, Moers assured. He also mentioned that customers aren't concerned because they want the car to be launched without issue, as some have experienced problems with previous hybrid hypercars they've owned.

Other interesting tidbits revealed by the AMG boss is that the One will sound just like an F1 car and when pushed to the limits will feel like a GT3 race car in fast forward. He also confirmed an 11,000-rpm redline (down on F1's 14,000 rpm), an engine life of 50,000 kilometers after which a rebuild will be neccessary, a top speed of 217 mph, and the possibility of slick tires being made available for drivers that want to track the car. AMG's tire partner in the project is Michelin.